(CNN) With all the glass ceilings that she's broken in her career, Kamala Harris has always resisted talk about her pioneering firsts.
But when Joe Biden chose her as his running mate Tuesday, she made history again as the first Black and South Asian woman to grace a presidential ticket, and the decision sealed her place as the presumptive Democratic nominee's bridge to the next generation while also demonstrating that she is a running mate who defies easy definition.
Harris, 55, had always appeared to be the strongest choice for Biden, 77 -- vetted and tested through the rigors of the campaign trail in her own White House bid; a fierce adversary of President Donald Trump who had already shredded many of his nominees with her unsparing prosecutorial style in Congress; and a charismatic Black woman who could speak personally to the racial injustices that have surged to the forefront of America's consciousness.
But for Biden, who played a central role in Barack Obama's history-making journey to the presidency in 2008 and now presents himself to voters as a transitional figure, choosing Harris was also a way to shape the future of the Democratic Party.
By selecting a Black woman -- whose background as the daughter of Jamaican and Indian immigrants embodies the new American story -- he recast the Democratic power structure for years to come.
With the pick, Biden acknowledged the disappointment that some Democratic women still feel nearly four years after Hillary Clinton lost her bid to be the first female president. That sting had persisted in a historic year when a record number of women ran for president as major contenders yet did not advance into the final round, despite all the energy of the women's marches and the resurgence of feminism in reaction to Trump.
Now Democratic women and women of color, who are the driving force of the party, will see themselves represented on the national stage.
Though vice presidential picks historically have not made a major impact on the outcome of presidential elections, the Biden campaign hopes that Harris will help shore up his support among suburban women who were drawn to her White House bid, older African American women who are the core of the Democratic Party, as well as younger Black voters, many of whom did not show up at the polls in 2016 for Clinton.
More than 20 years Biden's junior, Harris is also a vibrant and energetic pick who may help Biden address the concern among some voters about his age. By picking a former rival -- who punched him hard as she tried to carve her own path to the White House -- Biden drew a direct contrast with Trump, who has shown little capacity for forgiveness and has sought to punish anyone he believes has crossed him.
Biden and Harris will appear together as running mates for the first time on Wednesday in Wilmington, Delaware, to deliver remarks on their vision for restoring "the soul of the nation" and helping working families. They plan to hold a virtual grassroots fundraiser Wednesday evening.
The varied attacks unleashed on Harris from Trump and his allies Tuesday showed the difficulty of defining the former prosecutor, who was raised in Oakland and Berkeley, California, and went on to serve as district attorney of San Francisco and attorney general of California.
Trump rolled out a scattered, kitchen-sink-style list of criticisms of the senator from California during his news conference, attempting to brand Harris as a "big tax raiser," a "slasher of funds to the military," an advocate for "socialized medicine" and one of "the most liberal" members of the US Senate.
But the President seemed most fixated on drawing attention to Harris' past attacks on both Biden and then-Supreme Court nominee Brett Kavanaugh. The President repeatedly called her "nasty" in the sexist parlance that he so often uses to describe women he views as his opponents.
Playing into the hands of Biden's advisers -- who want to draw attention to the fact that Biden chose Harris despite her sharp critique, during a June 2019 debate in Miami, of his opposition to busing and his work with segregationist senators -- Trump said he was surprised that Biden had chosen someone who had been "very, very, nasty" to the former vice president.
"One of the reasons that it surprised me is -- she was probably nastier than even Pocahontas to Joe Biden," Trump said at the White House on Tuesday, employing the racially offensive name that he uses to describe Sen. Elizabeth Warren of Massachusetts, another former Biden rival.
"She said things during the debates, during the Democratic primary debates, that were horrible about sleepy Joe, and I wouldn't think that he would have picked her."
Trump also said he wouldn't forget Harris' interrogation of Kavanaugh, who was accused of sexual assault decades ago during the vetting process for his nomination (accusations Kavanaugh denied). From her perch on the Senate Judiciary Committee, Harris was one of his toughest interrogators, in video clips that went viral just like so many other sessions where she questioned Trump nominees in her courtroom style.
"That was a horrible event," Trump said Tuesday of Harris' intense questioning of Kavanaugh. "I thought it was terrible for her; I thought it was terrible for a nation. I thought she was the meanest, the most horrible, most disrespectful of anybody at the US Senate."
Though Trump initially said in 2019 that Harris looked like one of the strongest Democratic contenders when she announced her presidential run, he claimed Tuesday evening that she had been his "number one draft pick" during the veepstakes. He mocked her for doing "very poorly in the primaries," adding -- "and that's like a poll."
But the Trump campaign's challenge in categorizing Harris, given her varied biography and career, was evident in the first statement released about the pick from Trump's adviser Katrina Pierson.
In the contradictory statement, Pierson said Harris would try to "bury her record as a prosecutor, in order to appease the anti-police extremists controlling the Democrat Party," but also said Harris had "embraced the left's radical manifesto" and "is proof that Joe Biden is an empty shell being filled with the extreme agenda of the radicals on the left."
Biden had seriously vetted nearly a dozen contenders -- all women -- before making his selection, which unfolded with the utmost secrecy after a week in which he had spoken with the contenders either in person or in face-to-face meetings. A Biden official said the former vice president had called Harris 90 minutes before the announcement to offer her the job, according to CNN's Jeff Zeleny.
Given the nation's focus on race relations and the criminal justice issues that Harris has made the focus of her life's work -- from both inside and outside the system as prosecutor and lawmaker -- she was a natural fit for this moment in the view of many Democrats.
She was one of the leading sponsors in the US Senate of the recent legislation to curb police misconduct, and an outspoken advocate for revisions that would provide greater accountability for police. In his tweet announcing his choice Tuesday afternoon, Biden argued that Harris has long been a "fearless fighter for the little guy."
But in Harris, Biden also saw a kindred spirit of his son Beau, the former attorney general of Delaware who died in 2015 at the age of 46 after a battle with brain cancer. Beau Biden became friends with Harris when they were serving as attorneys general at the same time.
"Back when Kamala was Attorney General, she worked closely with Beau," Biden wrote in one of two tweets announcing the pick. "I watched as they took on the big banks, lifted up working people, and protected women and kids from abuse. I was proud then, and I'm proud now to have her as my partner in this campaign."
That personal connection clearly helped Biden work through any lingering hard feelings about Harris' attempts to derail his candidacy during the 2019 Miami debate. On Tuesday, Harris once again vowed to be a loyal partner to Biden as the presidential race rolls into the crucial final months.
"@JoeBiden can unify the American people because he's spent his life fighting for us. And as president, he'll build an America that lives up to our ideals," Harris tweeted. "I'm honored to join him as our party's nominee for Vice President, and do what it takes to make him our Commander-in-Chief."